2
Framework for Groundwater Protection at LANL

Los Alamos National Latoratory’s (LANL’s) groundwater protection program is framed by technical difficulties associated with the complex hydrogeology of the Pajarito Plateau, regulatory mandates for conducting the program, and citizens’ concerns about the program’s adequacy. This chapter provides an overview of these issues to provide a context for the remainder of this report.

Studies of groundwater beneath the LANL site have been ongoing throughout the site’s history. The U.S. Geological Survey began this work in 1945, and in 1949 the site initiated studies to monitor and protect its groundwater quality. A court decision in 1984 extended the Environmental Protection Agency’s (EPA’s) authority under the Resource Conservation and Recovery Act (RCRA) to regulate chemically hazardous waste at Department of Energy (DOE) sites. In 1986 EPA clarified its jurisdiction for mixed waste (waste that contains both chemically hazardous and radioactive constituents) and determined that states must include mixed waste in RCRA authorizations.1 The EPA and the New Mexico Environment Department (NMED) issued LANL an operating permit in 1989, which required monitoring of RCRA-regulated facilities.

In 1995 NMED notified LANL that there was insufficient information about the site’s hydrogeologic setting upon which to base approval of a waiver from its groundwater monitoring requirements. LANL developed a Hydrogeologic Workplan (LANL, 1998a) to refine its understanding of the site’s hydrogeology in order to design an effective monitoring network. NMED approved the workplan in 1998, and it was completed on schedule in 2004. In 2005 NMED issued an Order on Consent for Los Alamos National Laboratory2 that establishes schedules for additional investigations that will lead to a corrective action decision under the Order.

The committee’s study approximately coincided with the publication of a major report (LANL, 2005a), which described LANL’s site characterization activities under the Hydrogeologic Workplan, and the development of LANL’s 2006 Integrated Groundwater Monitoring Plan (LANL, 2006a). LANL developed the monitoring plan according to legal requirements set forth in the Consent Order.

TECHNICAL CHALLENGES CONFRONTING LANL’S GROUNDWATER PROGRAM

The Laboratory’s current understanding of the hydrogeology beneath the site is summarized in Sidebar 2.1. In brief, the site is very heterogeneous with both fast and slow pathways that may serve to transport contaminants from the surface to the groundwater. Groundwater itself occurs in three modes: near-surface groundwater in canyon alluvium, intermediate-perched groundwater in the vadose zone, and groundwater in the regional aquifer beneath the water table. Surface water (e.g., streams, runoff) can redistribute contaminants on the surface, move them into the near-surface groundwater, or transport them offsite toward the Rio Grande. Color Plates 1 and 2 illustrate these general hydrogeological features. Note that the vadose zone is the unsaturated region that extends vertically from the surface to the water table, as depicted at the back of the cross section shown in Color Plate 2.

Table 2.1 summarizes the site’s hydrological settings beginning at the mesa tops, where most sources of contamination are located, downward to the regional aquifer. The regional aquifer, which furnishes drinking water for residents of northern New Mexico, is relatively deep (approximately 1000 feet). Under the Hydrogeologic Workplan, 25 wells into the regional aquifer and 6 intermediate-zone wells were completed for hydrogeologic characterization (LANL, 2005a).

Technical and programmatic challenges encountered in drilling and completing these characterization wells are documented in a history of the drilling program that was

1

See http://www.epa.gov/radiation/mixed-waste/mw_pg4.htm.

2

Usually referred to as the Consent Order. This legally binding agreement among NMED, DOE, and the University of California was signed on March 1, 2005.



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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report 2 Framework for Groundwater Protection at LANL Los Alamos National Latoratory’s (LANL’s) groundwater protection program is framed by technical difficulties associated with the complex hydrogeology of the Pajarito Plateau, regulatory mandates for conducting the program, and citizens’ concerns about the program’s adequacy. This chapter provides an overview of these issues to provide a context for the remainder of this report. Studies of groundwater beneath the LANL site have been ongoing throughout the site’s history. The U.S. Geological Survey began this work in 1945, and in 1949 the site initiated studies to monitor and protect its groundwater quality. A court decision in 1984 extended the Environmental Protection Agency’s (EPA’s) authority under the Resource Conservation and Recovery Act (RCRA) to regulate chemically hazardous waste at Department of Energy (DOE) sites. In 1986 EPA clarified its jurisdiction for mixed waste (waste that contains both chemically hazardous and radioactive constituents) and determined that states must include mixed waste in RCRA authorizations.1 The EPA and the New Mexico Environment Department (NMED) issued LANL an operating permit in 1989, which required monitoring of RCRA-regulated facilities. In 1995 NMED notified LANL that there was insufficient information about the site’s hydrogeologic setting upon which to base approval of a waiver from its groundwater monitoring requirements. LANL developed a Hydrogeologic Workplan (LANL, 1998a) to refine its understanding of the site’s hydrogeology in order to design an effective monitoring network. NMED approved the workplan in 1998, and it was completed on schedule in 2004. In 2005 NMED issued an Order on Consent for Los Alamos National Laboratory2 that establishes schedules for additional investigations that will lead to a corrective action decision under the Order. The committee’s study approximately coincided with the publication of a major report (LANL, 2005a), which described LANL’s site characterization activities under the Hydrogeologic Workplan, and the development of LANL’s 2006 Integrated Groundwater Monitoring Plan (LANL, 2006a). LANL developed the monitoring plan according to legal requirements set forth in the Consent Order. TECHNICAL CHALLENGES CONFRONTING LANL’S GROUNDWATER PROGRAM The Laboratory’s current understanding of the hydrogeology beneath the site is summarized in Sidebar 2.1. In brief, the site is very heterogeneous with both fast and slow pathways that may serve to transport contaminants from the surface to the groundwater. Groundwater itself occurs in three modes: near-surface groundwater in canyon alluvium, intermediate-perched groundwater in the vadose zone, and groundwater in the regional aquifer beneath the water table. Surface water (e.g., streams, runoff) can redistribute contaminants on the surface, move them into the near-surface groundwater, or transport them offsite toward the Rio Grande. Color Plates 1 and 2 illustrate these general hydrogeological features. Note that the vadose zone is the unsaturated region that extends vertically from the surface to the water table, as depicted at the back of the cross section shown in Color Plate 2. Table 2.1 summarizes the site’s hydrological settings beginning at the mesa tops, where most sources of contamination are located, downward to the regional aquifer. The regional aquifer, which furnishes drinking water for residents of northern New Mexico, is relatively deep (approximately 1000 feet). Under the Hydrogeologic Workplan, 25 wells into the regional aquifer and 6 intermediate-zone wells were completed for hydrogeologic characterization (LANL, 2005a). Technical and programmatic challenges encountered in drilling and completing these characterization wells are documented in a history of the drilling program that was 1 See http://www.epa.gov/radiation/mixed-waste/mw_pg4.htm. 2 Usually referred to as the Consent Order. This legally binding agreement among NMED, DOE, and the University of California was signed on March 1, 2005.

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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report SIDEBAR 2.1 Overview of the LANL Site’s Geological and Hydrological Setting Los Alamos National Laboratory occupies about 40 square miles of the Pajarito Plateau in north-central New Mexico, approximately 60 miles north-northwest of Albuquerque and 25 miles northwest of Santa Fe, as shown in Chapter 1, Figure 1.1. The Plateau is located within the Española Basin of the Rio Grande Rift, a major North American tectonic feature; see Color Plate 1. The Española Basin, as well as the Pajarito Plateau on its western edge, is filled with Miocene and Pliocene-age sediments and volcanic rocks. The topographic plateau is bounded to the west by the Pajarito fault zone. The Pajarito Plateau is formed by Pleistocene Bandelier Formation ash-flow tuffs from the Jemez volcanic field, which cover older volcanic units and the basin-fill sediments. The Laboratory site is interlaced with finger-like mesas separated by deep west-to-east oriented canyons cut by streams. Mesa tops range in elevation from approximately 7800 feet on the flanks of the Jemez Mountains to about 6200 feet near the Rio Grande Canyon. Most of the mesas in the Los Alamos area are formed from Bandelier Tuff (Color Plate 2), which includes ash fall, ash fall pumice, and rhyolitic ash-flow tuff. Deposited by major eruptions in the Jemez Mountains’ volcanic center 1.2 million to 1.6 million years ago, the tuff is more than 1000 feet thick in the western part of the plateau and thins to about 260 feet eastward above the Rio Grande. On the western part of the Pajarito Plateau, the Bandelier Tuff overlaps onto the Tschicoma Formation, which consists of older dacitic volcanics that form the Jemez Mountains. The tuff is underlain by the fanglomerate of the Puye Formation in the central plateau. Near the Rio Grande, the Bandelier Tuff is underlain by the Cerros del Rio basalts. These formations overlie the sediments of the Santa Fe Group, which extend across the Rio Grande Valley and are more than 3300 feet thick. Natural surface water in the Los Alamos area occurs primarily as short-lived stormwater or snowmelt runoff and in short ephemeral segments draining the uplands in the western portion of the Pajarito Plateau. Effluent from Laboratory and Los Alamos County operations also feeds the reaches of some streams. Perennial springs on the flanks of the Jemez Mountains supply base flow into the upper reaches of some canyons, but the volume is insufficient to maintain surface flows across the Laboratory site before the water is depleted by evaporation, transpiration, and infiltration. The site can be considered as having four hydrogeologic settings, as illustrated in the foreground of Color Plate 2, and described in Table 2.1. These settings range from the normally dry mesa tops to the regional aquifer. Surface water and alluvial groundwater provide pathways for LANL-derived contaminants introduced into canyons to migrate significant lateral distances. Stormwater and snowmelt are the dominant transport mechanisms for contaminants that are adsorbed to sediment, and the natural and effluent-supported “baseflow” conditions are most important for migration of contaminants in solution. Below the surface, groundwater occurs as: (1) water in shallow alluvium in canyons, (2) perched water (a body of groundwater above a less permeable layer that is separated from the underlying main body of groundwater by an unsaturated zone), and (3) the regional aquifer (depicted in Color Plate 2 as the saturated zone beneath the water table). Flow and transport of water in the vadose zone varies by rock type. Most of the plateau is covered with nonwelded to moderately welded Tshirege and Otowi Member ash-flow tuffs of the Bandelier Tuff. Unsaturated flow and transport through these nonwelded to moderately welded tuffs occurs predominantly through the porous matrix. On the western edge of the plateau, both fracture and matrix-dominated flow can occur, depending on the degree of welding of the tuff. In contrast to the flow behavior in the Bandelier Tuff units, groundwater flow in basalts occurs both as porous flow through breccia zones and as fracture flow where dense flow interiors are broken by interconnected fracture systems. Beneath the Pajarito Plateau, perched water bodies in the vadose zone may be important components of subsurface pathways. Depending on the geometry and hydrologic properties of perching layers, water within perched zones may be relatively stagnant or may flow laterally. It is postulated that saturated lateral flow along perching layers may facilitate movement of contaminated fluids toward the water table if the water is diverted laterally from an area with matrix-dominated flow (such as in porous tuff or brecciated basalt) to an area with fracture-dominated flow (such as in a dense, but fractured, basalt). Perched water is most often found in Puye fanglomerates, the Cerros del Rio basalt, and units of the Bandelier Tuff. The regional aquifer beneath the Pajarito Plateau is part of an aquifer that extends throughout the Española Basin (an area roughly 6000 km2). This aquifer is the primary source of water for the Laboratory, numerous pueblos, and the communities of Santa Fe, Española, Los Alamos, and White Rock. The sources of recharge to that portion of the regional aquifer beneath the Laboratory are diffuse recharge in the Sierra de los Valles and focused recharge from wet canyons on the Pajarito Plateau, as indicated in Color Plate 2. Natural discharge from the regional aquifer is primarily into the Rio Grande directly or to springs that flow into the Rio Grande. Flow modeling simulations also suggest that flow beneath the Rio Grande (west to east) may be induced by production at the Buckman wellfield just east of the Rio Grande, which supplies the city of Santa Fe. The aquifer is under water-table conditions across much of the Plateau, but exhibits more confined aquifer behavior near the Rio Grande. Hydraulic properties are highly heterogeneous and anisotropic, with vertical hydraulic conductivities much less than horizontal hydraulic conductivities, resulting in a muted response at the water table to supply-well pumping at greater depths. Imprinted on the natural variations in chemistry along flowpaths is the presence of contaminants historically released since the early 1940s when Laboratory operations began. The impacts to groundwater at the Laboratory have occurred mainly where effluent discharges have caused increased infiltration of water. The movement of groundwater contaminants is best seen through the distribution of conservative (non-sorbing) species. Under many conditions contaminants like chromate, nitrate and residues of high explosives, tritium, and perchlorate move readily with groundwater. For some compounds or contaminants (americium, barium, cesium, plutonium, strontium-90, uranium, some high-explosive compounds, and solvents), movement can be slowed considerably or their concentrations decreased by adsorption or cation exchange, precipitation or dissolution, chemical reactions like oxidation/reduction, or radioactive decay. SOURCES: Excerpted and modified from LANL, 2005a,b.

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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report TABLE 2.1 Hydrogeologic Settings at the Los Alamos National Laboratory Region Subregion Location Characteristics Mesas Dry mesas Bandelier Tuff, eastern part of Laboratory Low rainfall, high evaporation, efficient water use by vegetation. Net infiltration rates for dry mesas are less than 10 mm/yr and typically on the order of 1 mm/yr or less. Enhanced air circulation through the mesas may enhance evaporation within the mesa interior, limiting downward moisture movement.   Wet mesas Bandelier Tuff, western part of Laboratory Higher rainfall and increased welding of the tuff, compared to mesas on eastern part of Laboratory. Transient zones of higher saturation, related to fractures and lithologic variations. Increased potential for vertical transport of water and solutes compared to dry mesas. Some evidence of fast fracture flow with slow transport through the matrix.   Disturbed mesas Liquid waste disposal, asphalt covers, devegetation Rainfall and liquid disposal could cause leaching. Investigations indicate limited vertical transport of water and solvents.   Perched water tables On lithologic interfaces within the unsaturated zone Potential storage of water and solutes. Alluvium NA Unconfined, perched on underlying Bandelier Tuff, Cerros del Rio basalts, or Puye Formation Historical or current anthropogenic liquid discharges combined with runoff. Source of recharge to underlying intermediate, perched zones and to the regional aquifer. Seasonal water tables (highest in late spring from snowmelt runoff and mid- to late summer from thunderstorms). Percolation from the alluvial groundwater might occur as saturated flow, which could rapidly transport solutes to the underlying intermediate or regional groundwater. Intermediate Perched NA Beneath major canyons and in the western part of the Laboratory Lateral extent and volumes of saturated zones uncertain. May provide flow and transport paths from beneath one canyon to another. Regional Aquifer NA Beneath entire site Significant heterogeneity and anisotropy. Receptors associated with water supply wells, springs. SOURCES: LANL, 2005a, Sections 2.3 (geologic), 2.5 (alluvial), 2.6 (vadose zone), 2.7 (perched), and 2.8 (regional); LANL, 2005c; and LANL, 2006c, Appendix A, which lists (in tabular form) conceptual model elements for each watershed at LANL. released by LANL in December 2006 (Nylander, 2006).3 While drilling a 1000-foot-deep well is not especially problematic—the petroleum industry routinely drills wells that are miles deep—the often conflicting requirements for data gathering at multiple depths both during drilling and after completion, drilling with little or no fluids (“muds”)4 to avoid changing the natural conditions around the borehole, and schedule and budget constraints made the work difficult. Compromise solutions to meet these requirements led to controversies about the quality and reliability of data provided by these wells (DOE, 2005; Ford et al., 2006; Ford and Acree, 2006; Gilkeson, 2006a,b). Aware of the challenges in carrying out the Hydrogeologic Workplan, LANL sought and received independent technical advice. Early in the program, LANL commissioned Schlumberger5 to review LANL’s drilling methods and management. In general the review (Schlumberger, 2001) recommended that LANL develop better knowledge and use of industry practices. An External Advisory Group (EAG; Anderson et al., 2005) commissioned by LANL held semi-annual meetings with LANL personnel and stakeholders from 1998 to 2003 and close-out meetings in 2004 and 2005. The EAG’s final report emphasized the need to develop sitewide hydrogeological models, noting that: “LANL will never have enough field data to ‘fill the gaps’ (i.e., to integrate and interpolate) or to answer the most important questions (i.e., to predict [migration]) directly through sampling” (Anderson et al., 2005, p. 7). 3 C.L. Nylander, History of Drilling and Well Construction Decision-Making for Los Alamos National Laboratory’s Hydrogeologic Characterization Program and Groundwater Protection Program 1995-2006. 4 Drilling fluids are used to lubricate the drill bit, remove cuttings, and stabilize the borehole; see Chapter 5. 5 Schlumberger is an international oilfield and information services company. The report “Evaluation of Environmental Drilling Program at Los Alamos National Laboratory” was received by LANL in July 2001.

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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report While the EAG judged that modeling activities conducted under the Hydrogeologic Workplan were less directed at developing a monitoring plan than initially envisioned, sufficient data currently were available to do so. The EAG suggested beginning with simpler models and integrating them. In its final report, the EAG was generally complimentary of LANL’s progress under the workplan. In remarking on LANL’s accomplishments and on the complexity of the site’s hydrology, the EAG stated that “the many findings help unscramble the omelet that is the Pajarito Plateau” (Anderson et al., 2005, p. 2). In approaching this study, the committee recognized that the technical issues confronting LANL’s groundwater protection program have a long history and are complex. This study is clearly not the first time that LANL has sought independent technical advice. The study, however, comes at a critical juncture as LANL moves from site characterization under the workplan to establishing its groundwater monitoring program. STAKEHOLDERS’ CONCERNS ABOUT GROUNDWATER PROTECTION AT LANL The term “groundwater protection” is prominent in the committee’s task statement (see Chapter 1, Sidebar 1.1). During the committee’s early deliberations, several members raised the question of what exactly is meant by the term. It appeared that DOE, its regulators, and public stakeholders had different views of what would constitute groundwater protection at LANL. Accordingly, for its third meeting6 the committee organized part of its plenary session around the questions: “What constitutes groundwater protection?” and “What should be the objectives of LANL’s groundwater protection program?” Representatives from six organizations were invited to give five- to seven-minute commentaries on these questions and then participate in a question and answer session, which was open to all attendees. Invited organizations were selected by the committee to reflect a variety of viewpoints, based on their participation in the earlier meetings and advice from the Northern New Mexico Citizens’ Advisory Board (NNMCAB). The viewpoints presented are summarized in Sidebar 2.2.7 The committee considered these views on groundwater protection in approaching its task statement. More importantly, the committee hopes that further discussion of these fundamental questions by LANL, its regulators, and public stakeholders will help promote agreement on what LANL’s groundwater protection program should accomplish. THE REGULATORY FRAMEWORK FOR GROUNDWATER PROTECTION AT LANL— THE CONSENT ORDER Radioactive and hazardous waste management is a complex issue, not only because of the nature of the waste, but also because of the complicated regulatory structure for dealing with it. There are a variety of stakeholders affected, and there are several regulatory entities involved. Federal government agencies involved in radioactive waste management include the DOE, the EPA, the Nuclear Regulatory Commission (USNRC), and the Department of Transportation.8 In addition, these federal agencies may share or designate portions of their authorities to the states. The Atomic Energy Act (42 U.S.C. Sect. 2011-Sect. 2259) (AEA) delegates the regulation of nuclear energy primarily to DOE, the USNRC, and the EPA. DOE authority extends to source material, special nuclear material, and byproduct material containing radioactive components. With respect to byproduct material, DOE issued a final rule (10 Code of Federal Regulations Part 962) with a much narrower interpretation of the term as it applies to radioactive material having a hazardous waste component (i.e., mixed wastes). Under this rule DOE retains authority under AEA for the actual radionuclides in byproduct material. Any non-radioactive hazardous component of the material will be subject to regulation by EPA or an authorized state program under the RCRA. Generally speaking, EPA’s role in radioactive waste management is to develop and issue radiation protection standards and to provide technical expertise during site cleanup. EPA also works with and provides assistance to other federal agencies and state and local governments on radioactive waste issues. Under the Comprehensive Environmental Resource, Compensation and Liability Act, EPA has the authority to respond to releases or threatened releases of hazardous substances, pollutants, and contaminants, including radionuclides. RCRA, 42 U.S.C. parts 6901 to 6992(k), authorizes regulation of hazardous waste. Under the Act, Congress specifically waived the sovereign immunity of the United States for actions brought under state laws implementing RCRA. New Mexico enacted the New Mexico Hazardous Waste Act (HWA), New Mexico Statutes Annotated (NMSA) 1978, parts 74-4-1 to 74-4-14, as the state equivalent to RCRA, to authorize New Mexico’s regulation of hazardous waste. In order to implement the statute, New Mexico promulgated the Hazardous Waste Management Regulations (HWMR) 20.4.1 New Mexico Administrative Code (NMAC). Authority to administer and enforce the state hazardous waste program under its regulatory framework was delegated 6 Appendix A gives a list of committee meetings and presentations to the committee. 7 Sidebar 2.2 was presented in the committee’s Interim Report (NRC, 2006), which summarized the committee’s information-gathering meetings. 8 Generally speaking, the USNRC and Department of Transportation have authority over DOE radioactive wastes only when the wastes are shipped away from a DOE site, for example for disposal in a privately owned facility.

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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report SIDEBAR 2.2 Stakeholder Perspectives on Groundwater Protection Concerned Citizens for Nuclear Safety (CCNS) Groundwater protection is very basic and simple. It means: Protecting water supplies now and in the future; Collecting representative groundwater samples in compliance with the Clean Water Act and the Resource Conservation and Recovery Act; Imposing fines for facilities that are not in compliance with the law; Having answers to questions about where contaminants are going; Considering and including wastes buried in unlined pits, trenches, and shafts in monitoring and remediation programs; and Removing sources of contamination. Department of Energy-National Nuclear Security Agency (DOE-NNSA) Groundwater protection is achieved by meeting specific requirements that are spelled out in: The NMED Order on Consent for the Los Alamos National Laboratory; New Mexico Water Quality Control Commission (WQCC) regulations; and DOE Orders. DOE requires maintaining groundwater quality adequate for its highest beneficial use, which DOE considers to be extraction of drinking water from the regional aquifer. Environmental Protection Agency (EPA) EPA’s standards and policies for groundwater protection include the following: Meet appropriate cleanup standards as determined by a site-specific risk assessment. EPA standards range from one excess cancer in 10,000 exposed people to one excess cancer in 1 million exposed people (i.e., a risk range of 10−4 to 10−6). Address all exposure points from groundwater, such as groundwater to surface water, groundwater to springs, or indoor inhala-tion of contaminants from groundwater (e.g., radon). Be flexible in the cleanup standards according to usage classification of the water (e.g., residential, industrial, farming) and the natural quality of the groundwater itself. New Mexico Environment Department (NMED) What constitutes groundwater protection at LANL is specified in the: New Mexico Water Quality Act; New Mexico WQCC Regulations; and the Order on Consent for Los Alamos National Laboratory. According to both the WQCC regulations and the Consent Order, “groundwater” means interstitial water that occurs in saturated earth material and which is capable of entering a well in sufficient amounts to be used as a water supply. The WQCC regulations include the notion of groundwater that can be “reasonably expected to be used in the future” and states that risk from a toxic pollutant must not exceed one cancer per 100,000 exposed persons. The Consent Order requires cleanup of groundwater when the lower of either WQCC standards or EPA maximum contaminant levels (MCLs) is exceeded. Northern New Mexico Citizens’ Advisory Board (NNMCAB) Contamination at LANL arose in the context of ensuring the nation’s nuclear security. Similar commitment and continuity in monitoring and site remediation is required, including: Monitoring and detecting trace-level contaminants in order to anticipate significant migrations. Improving flow models. (Must understand groundwater flows because the only alternative is to remove the sources, which would be very difficult.) Taking a very long-term perspective, perhaps 2000 years. Such long times are unique—beyond our experience. Models that can reliably predict contaminant behavior over such times are necessary. Be prepared for surprises and incorporate uncertainty in models. Following a risk-informed decision process. Pueblo de San Ildefonso Land, air, and water are sacred. They must be viewed holistically, so that groundwater cannot be separated from the others. LANL occupies the ancestral domain of San Ildefonso. All environmental media have been contaminated by LANL activities; Contamination violates the sanctity of religious and cultural resources; and therefore, Contamination at any level is unacceptable. Los Alamos National Laboratory (LANL) LANL summarized its goals for groundwater protection during the opening session of the plenary, as follow (Dewart, 2006): Demonstrate compliance with applicable standards and regulations; Protect the drinking water supplies of surrounding communities; Protect the quality of groundwater moving from LANL to offsite locations; and Protect the quality of water in springs and the Rio Grande.

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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report to the New Mexico Environment Department’s predecessor agency by the EPA in April 1985; New Mexico received authorization for the corrective action portion of the federal program in January 1996. Both the HWA and the HWMR require corrective action at sites, such as LANL, where hazardous waste or its constituents have been released into the environment. A Hazardous Waste Facility Permit under HWMR was issued to the University of California (UC) and DOE (DOE as owner, and both DOE and UC as co-operators of LANL) in November 1989. A permit addressing corrective action at LANL was issued by EPA in March 1990. Compliance Order on Consent Preceding and during the period of the Hydrologic Workplan (1998-2004), NMED concluded that LANL’s efforts and progress in addressing the contamination at the site were insufficient. Because NMED judged a variety of technical and regulatory issues were not being fully addressed, NMED issued an Order pursuant to the HWA on November 26, 2002, to DOE and the UC. This Order declared that the contamination at LANL constituted an imminent and substantial endangerment to human health and the environment, and directed DOE and UC to undertake certain prescribed actions to address the endangerment. DOE and UC subsequently sued the State of New Mexico. The settlement negotiations that ensued culminated in the Compliance Order on Consent (Consent Order, see Sidebar 2.3) that recognized the results of previous investigation work, but mandated additional investigation as necessary and approved by NMED, to fully characterize the nature, extent, fate, and transport of contaminants that have been released to the environment, including soil, sediment, surface water, and groundwater, to determine the need for and scope of corrective action. The Consent Order replaced the substantive provisions of the LANL corrective action permit issued by EPA. The overall goal of the Consent Order involves determining the nature and extent of releases of contaminants at or from LANL, and using that information to make informed remedy selections for LANL’s contaminated sites. It seeks to establish an aggressive, transparent, and collaborative process that ensures that results will be achieved in a timely fashion. The Consent Order is intended to accelerate the pace of investigation and cleanup of the site. The Order places LANL under an enforceable schedule under the HWA that requires completion of all remedial activities by 2015 (Bearzi, 2006). The technical requirements of the Consent Order include the following: The completion of investigations currently under way for several waste management units at LANL; Specific investigation requirements for high-priority sites including investigations of separate SIDEBAR 2.3 What Is a Consent Order? Federal and state regulatory agencies may issue orders in situations involving violations of statutes, regulations, permits, or other orders. In these orders a regulatory agency is authorized to assess penalties, require corrective or remedial actions, and modify, suspend, or revoke permits. Under RCRA (or an equivalent state law), EPA or states may also issue orders addressing imminent and substantial endangerments to human health and the environment. Consent Orders are a mechanism to resolve such situations through negotiation. Consent Orders memorialize such negotiations in a legally enforceable document. In this respect, orders issued after administrative hearings and Consent Orders are quite similar to statutes and regulations in the sense that failure to obey an order is punishable under the law. Consent Orders are designed to bridge noncomplying activities into compliance and must be limited in time and scope. The contents of Consent Orders will vary depending upon the regulatory program involved and an agency’s enforcement protocols. They may include the following provisions: Remedial Program—The Order may require the respondent to remedy any environmental, natural resource, or public health damage resulting from the violations. Compliance Schedules—The Order may include a detailed compliance schedule that (1) provides monitorable milestone dates that correct all violations and lead to full regulatory compliance by the soonest feasible date; and (2) requires the implementation of any other remedy by certain dates. Interim Controls—The Order may require the use of effective and feasible controls to minimize any environmental threat or damage during the interval between the execution of the Order and the date of final compliance in the compliance schedule. Penalties—The Order may include penalties consistent with an agency’s policies on the subject. watersheds within LANL, and investigations of individual waste management units and technical areas at LANL; General characterization requirements for sites not yet addressed under the LANL environmental restoration program; Specific methodology and procedures for investigation, sampling, and analysis; Requirements for groundwater monitoring, drilling, and well construction; Requirements for identification of cleanup alternatives and corrective actions, including interim measures, to clean up contaminants in the environ-

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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report ment and to prevent or mitigate the migration of contaminants at or from LANL; The implementation of cleanup measures for LANL as agreed upon and approved by NMED; Methods for establishing screening and cleanup levels for contaminants at LANL that meet state environmental standards; Reporting and submission requirements; and Schedules for reporting, workplan submittals, and corrective action completions. The Consent Order contains no specific requirements for radionuclides or the radioactive portion of mixed waste at LANL because the state does not have jurisdiction over regulation of such substances. The DOE may voluntarily include information about radionuclides in any plan, report, or other document. However, such submission is not enforceable by any entity, including the state, under the Consent Order, because such information falls wholly outside the requirements of the Consent Order. Groundwater Investigation Under the Consent Order, LANL is to conduct investigations of groundwater in accordance with NMED-approved workplans to fully characterize the nature, vertical and lateral extent, fate, and transport of groundwater contamination originating from the Laboratory to determine the need for, and scope of, corrective action. The investigation is to include an evaluation of the physical, biological, and chemical factors influencing the transport of contaminants in groundwater. All data must be collected according to EPA-and industry-accepted methods and procedures. Sidebar 2.4 gives a synopsis of the 2006 Integrated Groundwater Monitoring Plan that LANL developed to meet requirements of the Consent Order. Chapters 4 and 5 deal in detail with technical issues related to monitoring at LANL. Implementation of the Consent Order began in March 2005 just as the Hydrogeologic Workplan was completed. Implementation of the groundwater monitoring requirements of the Consent Order fulfill the groundwater monitoring requirements of the NMSA Hazardous Waste Regulations. Based on the results of groundwater investigations conducted in accordance with the Consent Order or other information, NMED may require modification of the number and location of piezometers and wells to be installed as part of the Consent Order. Groundwater monitoring wells and piezometers must be designed and constructed in a manner that will yield high-quality samples, ensure that the well will last the duration of the project, and ensure that the well will not serve as a conduit for contaminants to migrate between different stratigraphic units or aquifers. SIDEBAR 2.4 The 2006 Integrated Groundwater Monitoring Plan The 2006 Integrated Groundwater Monitoring Plan for Los Alamos National Laboratory (LANL, 2006a) issued in July 2006 is an extension of the InterimFacility-Wide Groundwater Monitoring Plan (LANL, 2006c) that LANL issued in April 2006. The interim plan is included as section 1 of the Integrated Plan. Section 2 of the Integrated Plan describes LANL’s monitoring of water supply wells in Los Alamos County and the city of Santa Fe. This monitoring is conducted under DOE Orders. Section 3 describes LANL’s monitoring of groundwater and surface water at locations within Pueblo de San Ildefonso, which is performed under a Memorandium of Understanding between the Pueblo and DOE. Section 4 describes monitoring to satisfy conditions of two groundwater discharge permits under New Mexico WQCC regulations. According to the Integrated Plan, the purpose of monitoring is to: Determine the fate and transport of known legacy-waste contaminants; Detect new releases; Determine efficacies of remedies; and Validate proposed corrective measures. LANL intends that the work under the Integrated Plan will identify potential risks to the regional aquifer as a drinking water source and monitoring data will be used in risk-based decision making as stipulated in the Consent Order. Groundwater Cleanup Levels Since the eventual goal of the program is the restoration and cleanup of the environment in and around LANL, decisions must be made regarding groundwater cleanup levels and their regulatory basis. The Consent Order follows the principle that groundwater cleanup levels for human health should usually be developed using existing standards (e.g., drinking water standards) when they are available and should be applied to protect against current and reasonably expected exposures. The Order establishes the process whereby NMED and LANL must refer to EPA guidance, Handbook of Groundwater Protection and Cleanup Policies for RCRA Corrective Action as amended (EPA, 2004a), in developing and applying groundwater cleanup levels. As provided in that guidance,

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Plans and Practices for Groundwater Protection at the Los Alamos National Laboratory: Final Report states may take a more stringent approach than EPA would otherwise use for making groundwater use and cleanup decisions. The WQCC groundwater standards, including alternative abatement standards (20.6.2.4103 NMAC), and the drinking water MCLs adopted by EPA under the federal Safe Drinking Water Act (42 U.S.C. §§ 300f to 300j-26) or the Environmental Improvement Board (20.7.10 NMAC) are cleanup levels for groundwater. If both a WQCC standard and an MCL have been established for an individual substance, then the lower of the two levels will be considered the cleanup level for that substance.